김종관 한국건설기술연구원 지반연구본부 수석연구원

김종관 한국지반공학회 2023 지반 : 한국지반공학회지 Vol.39 No.4

담낭암으로 오인한 담낭관 결석 및 담낭염의 증례 1예

김종관,박홍배,최병인,여향순,김순호,강명원,이상석,오필석 대한소화기내시경학회 1989 Clinical Endoscopy Vol.9 No.2

A 56 year old female was admitted because of the right upper quadrant mass for 4 days. She complained of intermittent colicky RUQ pain, fever and chills. So diagnostic procedures was performed: Blood chemistry testings. Ultrasonography. Barium enema, Liver scan, Hepatobiliary scan, ERCP and Abdomen CT, which diagnosed as gall bladder carcinoma. So explolaparotomy was performed and gross operative finding was gall bladder carcinoma with metastatic lymph node and cystic duct stone. So cholecystectomy, hemigastrectomy and anterior segmentectomy of right liver was done. But the biopsy result was cystic duct stone, cholecystitis and gall bladder empyema.

성견 1면 치조골 결손부에서 특수제조된 Calcium Sulfate Paste가 치주조직 치유에 미치는 영향

김종관,Kim, Chong-Kwan 대한치주과학회 1999 Journal of Periodontal & Implant Science Vol.29 No.1

The purpose of this study was to evaluate the effect of modified calcium sulfate paste on periodontal regeneration. l-wall intrabony defect(mesio-distal width: 4mm, depth: 4mm) was surgically created on the distal side of P2 and mesial side of p4 in four dogs. The control group(GFS) was treated with conventional flap operation alone, and the experimental group(CS) was treated with conventional flap operation with modified calcium sulfate paste application. Both control and experimental groups were sacrificed after 8weeks of healing period, The results of histological and histometric observations were as follows. 1. The length of the junctional epithelium was 0.41${\pm}$0.01mm in the control groups, 0.47${\pm}$0.01mm in the experimental group. 2. The connective tissue attachment was 0.28${\pm}$0.02mm(6.15${\pm}$0.28%) in the control group, 0.18${\pm}$0.01mm(3.41${\pm}$0.14%) in the experimental group. The control group showed more connective tissue attachment. 3. The new cementum formation was 3.80${\pm}$0.06mm(84.80${\pm}$0.33%) in the control group, 4.49${\pm}$0.06mm(87.57${\pm}$0.15%) in the experimental group. Both groups showed a lot of new cementum formation. 4. The new bone formation was 1.43${\pm}$0.03mm(32.37%) in the control group, 2.04${\pm}$O.09mm(40.94%) in the experimental group. 5. The inflamatory cells were observed partially around resorbed calcium sulfate in the connective tissue of the experimental group. 6. Partially resorbed calcium sulfate were found within the connective tissue, around alveolar bone, and in the newly formed alveolar bone, On the basis of these results, newly formed calcium sulfate paste enhanced new bone formation and new cementum formation. The resorption rate of calcium sulfate seems to be controlled by the add-in compounds. Thus research about biocompatibility and adequate resorptionrate is required to develop a improved material.

GTR치료시 e-PTFE 차단막의 노출에 따른 하악이개부의 치유효과

김종관,김준일,Kim, Chong-Kwan,Kim, Joon-Il 대한치주과학회 2000 Journal of Periodontal & Implant Science Vol.30 No.3

In order to evaluate the effects of the early exposure of e-PTFE membrane on the periodontal regeneration, 21 cases of 21 patients diagnosed as the chronic adult periodontitis were evaluated. All were class II furcation involvement cases. The control group was composed of 7 cases treated only by the flap operation. 14 cases were treated by the e-PTFE membrane as the experimental group, the membranes of 7 cases were exposed more than 1mm during healing period, which were named as the experimental group I, and the others, experimental group II. Clinical parameters such as probing pocket depth, clinical attachment level, bone probing depth, and gingival recession were recorded before the treatment and 6 months after the treatment. The results were as follows. 1. Significant probing depth reductions were observed for all groups(p<0.05), but no group shows significantly greater reductions than another. 2. Significant clinical attachment gains were observed for the experimental group II(p<0.05), no significant gains were observed in the other groups. 3. Significant bone probing depth reductions were observed for the experimental group II(p<0.05), no significant reductions were observed in the other groups. 4. All but the experimental group II exhibited a significant increase in gingival recession(p<0.05). The result suggested that is case of the e-PTFE membrane is exposed, the result is similar to that of flap operation without membrane. Therefore selecting the proper treatment case, intricate surgical procedure and infection control are essential for minimizing the chance of membrane exposure and finally for the good treatment results.

공구 중량조건에 의한 주축변위 특성연구

김종관,이중기,김상복 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.4

In order to examine spindle deformation characteristics that affects the performance of dynamic cutting accuracy due to tool weight variation in a experimental spindle, thermal deformation value of operrative spindle by the axial displacement and the radial run out was measured according to the rise of spindle temperature through the laps of operation time and the change of rotational speed under the tool weight variation. A qualitative summary is as follows: 1) The results show that the tool weight affects the spindle temperature variation in a experimental spindle. 2) Radial run out and axial displacement was measured according to the rise of the spindle temperature and the performance of dynamic cutting accuracy was affected by the tool weight variation. 3) Axial displacement is 1.3 times larger than the radial run out in a experimental spindle conditions. 4) Axial displacement is continuously elongated when the tool weight is repeatly exchanged since the spindle themal deformation, however, when the same tool weight is used, the displacement is still constant.

벤처기업의 성과에 영향을 미치는 요인에 관한 연구

김종관,이용탁 釜山 大學校 經營 經濟 硏究所 2001 經營 經濟 硏究 Vol.20 No.1

본 연구는 벤처기업의 성과에 영향을 미치는 요인들에 관하여 먼저 선행연구된 문헌들의 고찰을 통한 문헌연구와 이에 근거하여 벤처기업의 성과향상을 위한 다차원적인 측면들에 대한 통합적인 실증조사로 국내벤처기업의 성과에 영향을 미치는 요인들을 파악하고자 하였다. 따라서 본 연구에서는 벤처기업에 영향을 미치는 요인들로 창업자의 심리적 특성, 벤처기업이 속한 산업내의 경쟁강도, 조직의 내부능력, 그리고 차별화전략으로 범위를 국한하여 성과에 미치는 영향을 상호 복합적인 관점에서 규명하였다. 그 결과로 먼저, 벤처기업이 속한 산업에서의 심한 경쟁강도는 벤처기업의 성과에 부정적인 영향을 미치는 것으로 나타났으며, 다음으로 창업자가 지니고 있는 성취동기나 위험감수성향, 그리고 내재적 성향과 같은 심리적 특성은 벤처기업의 성공에 중요한 영향을 미치고 있음이 파악되었다. 아울러 벤처기업의 내부능력이나 차별화전략은 성과에 정의 영향을 미치고는 있으나 통계적으로 유의한 결과를 나타내지는 못하였다. 그러나 업종에 따른 벤처기업간 내부능력과 차별화전략은 차이를 보일 것으로 예상할 수 있을 것이다.

광탄성 효과에 의한 광섬유 격자의 특성 변화

김종관,정해양 경희대학교 자연과학종합연구원 2000 자연과학논문집 Vol.6 No.-

편광유지 광섬유의 광탄성 효과를 실험적으로 조사하였다. 편광유지 광섬유 격자의 광축과 수직 방향으로 스트레스가 가해지면 격자에 의한 반사 파장이 이동하고 반사 스펙트럼은 2개의 봉우리로 갈라지는 것을 관측하였다. 이동한 파장은 가해진 스트레스의 크기와 비례하며 입사광선이 편광유지 광섬유의 복굴절 축중 slow 방향으로 편광되어 있고 fast 방향으로 스트레스가 가해지는 경우 그 효과가 가장 큰 것을 발견하였다. We report on strong effects of uniaxial compressive stress applied on Bragg gratings written in polarization maintaining optical fibers. The splitting of reflection peaks due to non-uniform distribution of stress in gratings is observed. Under the stress reflection peaks shift in wavelength. The amount of the shift is proportional to the stress. The effect of the stress on the reflection spectrum is the greatest when input polarization of light is in the slow axis while the stress is applied in the fast axis.

기어의 백래쉬를 고려한 승용차 조향계의 동특성 연구

김종관,김경석,송상기,정진형 한국공작기계학회 1996 한국생산제조학회지 Vol.5 No.3

The problem related to the rotational vibration at steering wheel end of passenger cars during high speed driving is investigated. To analyze vibration of steering wheel, a steering system of passenger car is modelled in twelve degrees of freedom including backlash effect of rack and pinion gear system. The one degree of freedom system with backlash in investigated by the analytical method . Consequently the skeleton curve and the frequency response curves are computed. The steering system is analyzed by the numerical simulation using the 4th order Runge-Kutta method, the obtained results are compared with the experimental data. Also the effects of the change of rack gear tooth stiffness and backlash on the acceleration level of steering wheel are investigated. As a result, it can be found that the acceleration level of steering wheel becames lower as the rack gear tooth stiffness becames higer, and that acceleration level becames high as the magnitude of backlash between rack and pinion gear increase.

기계적 치태조절 보조제로서 C31G, Listerine, CPC의 초기 치주염에 대한 임상적 효과

김종관,박지숙,한광희,서종진,최성호,조규성,채중규,Kim, Chong-Kwan,Park, Ji-Sook,Han, Kwang-Hee,Suh, Jong-Jin,Choi, Seong-Ho,Cho, Kyoo-Sung,Chai, Jung-Kui 대한치주과학회 1998 Journal of Periodontal & Implant Science Vol.28 No.4

The purpose of this study was to access the clinical effects of C31G, Listerine and CPC on the earlyx periodontitis when they were used as a adjunctives to the mechanical plaque control. Each groups were composed of 12 patients and in three test groups, C31G(Exp 1 group), Listerine(Exp 2 group) and CPC mouthrinse(Exp 3 group) were used three times a day. and as a control, placebo solution was used. Plaque index, gingival index, bleeding index, pocket depth and loss of attachment were measured as clinical parameters. After scaling and oral hygiene instruction, root planing is done two weeks later. During the eight weeks of experimental period, mouth gargling is done by all groups. The changes in the clinical parameters of the all sites were monitored every two weeks. The results were as follows : 1. The plaque index showed a siginificant difference in Exp 1 group compared with test 2 group after 2 weeks use of mouth rinse(P<0.05). 2. The gingival index showed a significant difference in Exp 1 group compared with baseline value(P<0.05) but there was no significant difference between the groups after 2 weeks use of mouthrinse (P<0.05). 3. The plaque index, gingival index and bleeding index showed a significant difference in all groups compared with baseline value after 4 weeks of root planing and mouthrinse use(P<0.05). but there was no significant difference between the groups(P<0.05). 4. Periodontal pocket depth showed a significant difference in all groups compared with baseline value after 4 weeks of root planing and mouthrinse use(P<0.05). and there was significant difference between the Exp 1 group and control group(P<0.05). 5. Loss of attachment showed a significant difference in all Exp groups compared with baseline value after 4 weeks of root planing and mouthrinse use(P<0.05). and there was significant difference between the Exp 1 group and control group(P<0.05). The results suggest that C31G, Listerine and CPC were effective for early periodontitis as a adjunctive to mechanical plaqe control.

치주염이환 치아표면에 부착된 치석과 치주조직의 형태 계측학적 연구

김종관,이승원,Kim, Chong-Kwan,Yi, Seung-Won 대한치주과학회 1997 Journal of Periodontal & Implant Science Vol.27 No.3

To verify the effect of subgingival calculus on the periodontal tissues in periodontitis and the effectiveness of supragingival scaling to remove the calculus, 30 teeth from healthy group (Probing pocket depth:$PPD{\leq}mm$: HP group), 15 teeth from moderate group ($4{\leq}PD<7mm$:MP group), 30 teeth from advanced group (PPD>7mm: AP group) were selected and supragingival scaling was performed before extraction of all experimental teeth. After careful extraction, the teeth were cleaned with saline and disclosed with toluidine blue and carefully examined the relationship and distance between the calculus attached on the root surface and periodontal tissues. As a result, it was; 1. The calculus was not discovered on the root surface of teeth in HP group, but was in MP and AP group, mostly on interproximal surface and furca area. The shape of the attached calculus was ovoid, trepazoid and polygonal and the calculus was distributed randomly over the root surface. 2. PPD was more than the distance between the gingival margin to the level of attached connective tissue in AP group rather than in HP and MP group. 3. The length of calculus was $2.7mm{\pm}.44mm$ in HP group and $4.1{\pm}.89in$ AP group. 4. The distance between the apical margin of calculus and the level of attached connective tissue was $2.4{\pm}.33mm$ in MP group and $3.4{\pm}.89mm$ in AP group. 5. The length of subgingival calculus was tended to increase in relation to the probing pocket depth. Therefore, it can be concluded, the calculus in periodontal pocket can not be removed completely with supragingival scaling. As the terminal part of calculus was far away with limited distance from the periodontal tissue, it can be said that the calculus was not a direct factor in destroying the periodontal tissue. In this study, the extent of the plaque was not verified but the location of calculus can be used in clinical practice for complete removal of calculus when the distance relation bewteen calculus and plaque will be known.